There has been a growing demand for devices made of all-optical components for performing such functions as amplification, commutation, switching and computing of optical signals without having to go through intermediate electronic stages.
One of the approaches proposed is based on a system wherein optical signals exist at all stages of signal processing with sufficiently high speed performance and simple configuration, preferably, by employing semiconductor components. Steady developments have been made towards this direction during the last decade.
One of such devices is disclosed in an article by Toolay et al., "High Gain Signal Amplification in an InSb Transphaser at 77 K", Appl. Phys. Letter, 43, 9,807-809 (1983), comprising an optical nonlinear phase modulator with mirrors formed on an optically nonlinear semiconductor material, e.g., InSb(indium/antimony). It is possible to obtain with this device which utilizes the optical nonlinearity of InSb, the effect of "the light by light" amplification by introducing two beams into InSb; a powerful beam for pumping and a weak one for carrying the data, resulting in the modulation of one beam with another and the amplification of the data-carrying optical signal (OS) upto 40 dB. This device is also known as a nonlinear Fabry-Perot interferometer (FPI). The advantages of this device include its small-sized design, high nonlinear factor and high gain factor. There exist, however, certain deficiencies in this device such as: the need for an external or outer pumping source; a single input and a single output channels; and complicated input/output beams due to the structural peculiarities of the device; the necessity for complete frequency coincidence of the FPI and the input OS; and the device being essentially a laboratory mock-up whose practicality is still unknown.
The closest prior art device to the present invention, from the technical point of view, may be the one called, "Optical Transistor" as described in U.S. Pat. No. 5,001,523 issued on Mar. 19, 1991, which is capable of commutating and amplifying optical signals as well as selecting the radiation of various frequencies by channels.
The advantages of this devices reside in its high amplification factor, the potential for commutation or switching of optical signals, its small-sized design, and the use of resonance rings as integral optic elements which permits the use of resonators with a high quality factor. There exist, however, certain deficiencies in this device including: a limited channel accessibility, a low sensitivity level for the input channels, and the lack of a multi-level system for the processing of the optical signals, i.e., lack of storage and logic capability.